Woodland butterflies: water draw-down, eutrophication and forest management

Water draw-down, eutrophication and forest management are impacting on woodland butterflies like the white admiral and map butterfly.

Trends in the white admiral

The white admiral used to be common, but since 1950 it has declined dramatically. Since 1992 the species has continued to decline. The white admiral lives in damp deciduous woodland where its host plant honeysuckle occurs.

One cause of its decline is large-scale forest management in which large areas are clear-felled and in which the forest edges are straight lines, leading to a more contiguous and monotonous forest composition. Honeysuckle is less likely to establish in such forest. Water draw-down is also a factor: the white admiral mainly occurs in woods where there is surface water.

The white admiral is on the Red List of butterflies.

Trends in the map butterfly

The map butterfly is one of the few woodland butterflies to have shown a sharp increase since 1950. Since 1992 its numbers have been more or less stable.

This species did not establish in the Netherlands until the 1940s. Around 1950 colonisation was still in full swing. Its host plant is the stinging nettle. The map butterfly has profited from the increase in stinging nettles in forests, forest margins, wooded banks and ruderal vegetation that has come about as a result of eutrophication.